Broaching machine



April 3, 1951 K F. A. BEST 2,546,962

BROACHING MACHINE Filed April 22, 1947 s Sheets-Sheet 1 E5 Fig-4 Fig-5 /NVN TOR FRANK ,4. 55s? ATTORNEYS F. A. BEST April 3, 1951 BROACHING MACHINE 5 Sheets-Sheet 2 Filed April 22, 1947 s a 5Q 7. N E .R v m w r M A F F. A. BEST April 3, 1951 BROACHING MACHINE 3 Sheets-Sheet 3 Filed April 22, 1947 INVENTOR I vdQm ATTORNEYS a 5 A K N M F Patented Apr. 3, 1951 s UNITED STATES PATENT OFFICE Claims.

The invention relates to novel and improved means and methods for joining complementary structural frame members.

The terminology structural member is here used to denote any one of the great variety of fabricated shapes obtainable in'hollow or open contours such as squares, rectangles, rounds, channels, etc. In commercial practice many such structural members are readily producible, for example by extrusion, although simple open channel types may also be fabricated by rolling.

In assembling fixed lengths of such structural members into a completed article, for example a.v rectangular window screen frame, by telescoping adjacent elements on the respective legs of right angled brackets as will later be described, it has been the experience of the art that it is difi'icult to obtain a proper alignment and planar registration of the outer surface of said adjacent elements. The basic cause of the trouble is that the customary longitudinal bore or groove in the structural member is often off center to a greater or lesser extent. This is true particularly with conventional extrusion processes since the anchoring of the spud or mandrel around which the extruded metal flows is susceptible to a certain amount of lateral drift. As a result the wall of the finished structural member may not be of the desired thickness throughout its whole sectional periphery, and if the ends of adjacent members are telescoped on a common bracket or .core, which may be straight or of any angularity orcurvature desired, the outer surfaces of the meeting ends of the adjoining members may not register accurately. Time consuming tailoring methods have heretofore been required for producing individual compensating corrections in registration, so as to secure a neater finished appearance.

An object of the present invention, therefore, is to provide novel and improved methods and means insuring accurate mutual alignment and orientation of adjoining structural members in ,an assembly.

A furtherobject of the invention is to provide novel and improved methods and means for accurately centering the axial apertures of cooperating structural members with respect to their outer surfaces so that said members may be telescoped on opposed ends of a common core with .their outersurfaces in coplanar relationship, or

otherwise in desired registration.

\ Another object of the invention is to provide novel and improved methods and means for simply and positively profiling the inner wall surface of the end of a structural member in accurately spaced relationship to its outer wall sur face, so that when two such ends are telescoped on the opposed ends of a common core their outer wall surfaces are properly registered and aligned.

A further object of the invention is to provide methods and means, as defined in the last preceding paragraph, wherein the inner wall surface of the end portion of the member and the outer wall surface of the core to be inserted therein are formed to a predetermined serrated contour of such character that the longitudinal central axis of the core coincides with the Iongitudinal central axis of the member, regardless of initial variations in member wall thickness.

A further object of the invention is to provide novel and improved means and methods for positioning and holding the end portion of a hollow structural member, and for broaching the inner wall surface of said member in such mariner that the broached inner contour is axially concentric with the outer end surface, and is likewise axially concentric with the outer surface of a supporting core.

A further object of the invention is to provide, for the purposes hereinbefore defined, a core having an external contour particularly adapted for a self-centering insertion in the abutting ends of adjacent hollow structural members. Other objects and advantages will be apparent from a study of the followin specification, in conjunction with the accompanying drawings, in which:

Fig. 1 is a view in elevation of one corner of a screen window sash, formed from the union of two extruded structural members telescoped on a common angle bracket or core;

I Fig. 2 is a sectional view, somewhat enlarged, taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in elevation of the bracket or core;

Fig. 4 is a transverse sectional view of a structural member of simple hollow rectangular contour, the bore being off center with respect to the outer walls; i

Fig. 5 is a view similar to Fig. 4, but showing the sectional appearance after a broaching operation in accordance with the present invention;

Fig. 6 is a side elevational view of a broach suitable for performing the operation indicated in Fig. 5;

Fig. 7 is a sectional view taken on the line 1-1 of Fig. 6;

Fig. 8 is a transverse sectional view of an off center bore in an extruded tube;

Fig. 9 is a view similar to Fig. 8 but showing the appearance of the tube after a broaching operation;

Fig. 10 is a sectional view of an open channel showing an undesired variation in wall thickness in the legs and base of the channel;

Fig. 11 is a view similar to Fig. 10, butshowing the sectional appearance after a broaching operation;

Fig. 12 is a top plan view of my novel apparatus for concentrically axially broaching hollow or open structural shapes;

Fig. 13 is a side elevational view. of the apparatus shown in Fig. 12;

Fig. 14 is an end view taken from the right of Figs. 12 and 13;

Figs. 15 and 16 are sectional views taken on the lines 15-15 and l6-l6of Fig. 13;

Fig. 17' is a sectional view taken on the line I'l'-ll of Fig. 12.

Before the present invention here illustrated is described in detail, it is to be understood that the invention here involved is not limited to the details of construction or the specific arrangement of parts herein illustrated or described, as the invention obviously may take various forms. It also is to be understood that the phraseology or terminology herein employed is for the purpose of description and not of limitation, the scope of the, present invention being defined in the appended claims.

Referring now to the drawings, and particularly to Figs. 1 to 3 inclusive, there is shown a fragmentary portion of a window screen sash formed by uniting two structural member elements 28 and 2 I. Said elements are telescopingly assembled on the respective arms of an angle bracket or core 22. It will be apparent that if the. axial bores in the respective ends of the members 2i] and 2| are off center with respect to their outer wall surfaces, the abutting end edges 23 and the corner portions 24 and 25' will probably be out of proper mutual alignment, thereby presenting a crude and unfinished appearance.

'22. It will be noted that the peripheral wall surfaces of thebracket are serrated by a series. of longitudinal parallel triangular ridges26; Fig. 4

shows the cross sectional appearance of: an extruded structural member as received from, the extrusion press, the eccentricity of. thebore being exaggerated for purposes of illustration. Reference character 21. denotes the axial center of the outer walls as determined by the intersectionof diagonals drawn from the outer corners. Reference character 28- denotes the axial center of. the walls of the bore as determined by: diagonals drawn from the inner corners. Figs. 6 and 7" show a broach 29 of rectangular section serrated to produce the inner wall contourshown in Fig. 5. The longitudinal walls of the broach taper backwardly from the leading end 30 to provide working clearance, the broach being d'ecentric broaching on the eccentrically formed' structural member 3| hereinabove noted, the effect of such concentric broaching is to place the broached profile 32 of the inner wall surface in axial alignment with the outer wall surfaces 33. In my apparatus. to be hereinafter described the advance of the broach is coaxial with the outer walls, and, the cutting teeth of the broach bite more deeply into the thicker walls than into the thinner walls. When an arm of bracket 22 is inserted in the broached opening, the axis of the arm will coincide with theaxial center 21 of both the outer walls and the broached profile of the inner walls. When two adjacent structural members, treated as just described, are assembled on the common bracket 22 their adjacent end surface portions are self-aligning, and produce an exact match.

Figs. 8 and 9 show the effect of concentric broaching on the cross sectional profile of a tubular member 38, and Figs. 10 and 11 show the effect of concentric broaching on the walls of an open channel member 39.

The manner of operation of the'broaching step, and the means whereby the same is accomplished, will now be disclosed.

Speaking generally, the apparatus comprises work guiding and clamping means, and broach holding, broach guiding, and broach advancing means. All such means will be described with particular reference to Figs. 12 to 17.

The apparatus is supported on a plate 40, which may be a table top, or work bench. The work receiving track or trough comprises a pair of vertical side plates 4| and 42 fixed in spaced parallel relationship on plate 40. A transverse floor plate 43 carried by said side plates supports the work piece 44, said Work piece being inserted from right to left in Fig. 13. Various adjustments of the Work-carrying channel for Width and height may be provided as desired, but the elements just described are here shown as fixed, being adapted for commercial production onone particular size and style of work piece.

The work is initially advanced to the desired broach-receiving position, as will hereafter be described, and is then securely held in said position by a vertically movable clamping plate 45 having an elongated transverse web or foot. 45 engageable with the work by downward movement ofthe foot. Said clamping plate is supported and actuated in the following manner. Fixed on plate 46 adjacent the work-receiving means is a clamp-supporting plate 4'! having attached to its upper end a transversebushing 48. The bushing has an axial aperture adapted to receive a stub shaft 49 eccentrically disposed on a cam head 50. The cam head is operated by a lever 53, and is here shown as integral with said lever. The upper portion of the. clamping plate 45: has a horizontal slot 541 adapted to slidably receive a. pin 55 fixed in the cam head 50. It will be apparent that clockwise movement of the lever 53 (Fig. 139' produces rising movement of the plate 45 and its clamping foot 46 sotha-t the foot moves out of contact withthe work 4'4.

counterclockwise swing of the lever 53 returns the foot 46 to its work-clamping position. Vertical movement of the clamping plate 45 is guided by a pair of pins 56 extending through slots 51 in the clamping plate and fixed in the Support 41. An additional guiding pin 58 passes through a. slot 59 in support 41 and is fixed in plate 45. The pins 55, 56 and 58 may conveniently be machine screws. Annular spacers 60 are carried on the shanks of screws 56 and 58 between the fixed plate 41 and the movable clamping plate 45. The machine screws are drawn up just tightly enough to permit Sliding movement of the clamping plate without side play. Buttresses 6| help to strengthen and support the fixed plate 47.

An elongated collar 64 is pivotally mounted on the shank of pin 55 in such manner that it rides within slot 54. It will be apparent that when lever 53 is moved counterclockwise, the right end (Fig. 13) of the collar eventually moves into contact with the right end of slot 54, thereby constituting stop means for lever travel in counterclockwise direction. This stop means likewise limits cam clamp travel. At such stopping point the clamp foot 46 should be in tightly gripping contact with the work.

The broaching mechanism and the guiding and holding means therefore will now be described.

An elongated housing 61 of tunnel-like character is disposed on base plate 40 and is spaced somewhat from the work holding means above described, but is axially aligned therewith. Longitudinally slidable within said housing is a sleeve-like guide 68. Movement of the guide is effected by a lever 69 pivoted at to a pillar H fixed on plate 40. The working end of the lever has a pivoted connection with a link 12 by means of a pivot pin 13. The other end of link 12 in turn has a pivoted connection through a pin 14 which passes through a slot and is fixed in the top wall of guide 68. Movement of lever 69 of course advances or retracts guide 68.

Sleeve 68 has a bored aperture 11 extending inwardly therein from the left end thereof (Fig. 13). This aperture is reduced in size at a stop shoulder 18. Between shoulder 18 and the right end of sleeve 68, the aperture is outwardly flared or bell-mouthed at 19 for a specific purpose as will appear. Slidable in aperture 11 is a plunger 80'. At the inner end of the plunger is a transverse slot 83 adapted to receive the shank of the broach 29 previously described. The broach shank is secured in slot 83 by means of pins 84. Advance and retraction of the plunger is eifected by a lever 85 pivotally mounted at 86 on a pilar 81 fixed to plate 40. The working portion of the lever is pivotally connected at 88 to a link 89 the other end of which is pivoted at 50 to the end of plunger 80. A stop collar 93 is fixed on plunger 80 so as to limit the working stroke of the plunger and consequently of the broach. The seeve 68 and the plunger 80 are movable independently of each other under the influence of their respective, levers 69 and 85.

A cycle of operation of the apparatus will now be described, in conjunction with thebroaching of the bore of a structural member such as is shown in Figs. 1 and 2.

The guide sleeve 68 is first fully retracted by means of lever 69 until its bell-mouthed end is withdrawn within housing 61. The broach and plunger assembly is also retracted as far as its linkage will permit by means of lever 85. The structural member 2| is inserted from the right (Fig. 13) into its guide track and advanced until its leading end abuts a stop 95 fixed with respect to the guide track. The work is then clamped in position by counterclockwise movement of lever 53.

By clockwise movement of lever 69 the guide sleeve 68 is advanced to the right, until the leading end thereof receives the end of the structural member in its bell-mouthed aperture. A selfcentering effect is produced between the flaring walls of the aperture, and the leading end of the work. The peripheral walls of the bell-mouthed aperture may be suitably cut away or tailored to accommodate variations in the contour of the leading end of the work. As soon as the work is suitably wedged into position in the aperture,

lever 85 is swungto produce advance of plunger thereby forcing the broach 29 into the bore in the work. In every work piece thus broached the inner profile is axially centered with relation to the outer surface walls, and all such work pieces will be mutually registrable on suitable brackets or cores, such for example as is shown in Fig. 3.

It will be obvious that the apparatus shown in Figs. 12 to 17 may be suitably modified to accommodate various structural shapes other than the one herein shown.

As a result of the application of the method above described to the structural members shown, when a set of members intended for assembly in a matched group are arranged so that adjacent ends of a pair of members are assembled on a common core, the outer surfaces of the x ,trable with the outer surfaces of another member also so treated, when they are assembled on a common core.

I claim: r

1. Apparatus of the character described forproducing a series of work pieces each having an aperture therein which is accurately dimensionally aligned with respect to its outer surface so that a pair of work pieces thus treated may be fixed in mutually end-abutting registrable relationship on a common supporting core, said apparatus comprising an elongated work piece holder having a bottom wall and a pair of spaced opposed side walls extending therefrom to define a work receiving channel open at its ends, stop means for establishing a fixed termination point for forward movement of said work piece in said channel, clamp means for retaining said work piece at said termination point, broachguiding means spaced from said. work piece holder and in longitudinal alignment with said channel, said guiding means comprising a tunneled housing, a guide sleeve telescopingly advanceable and retractable in said housing, said guide sleeve having an axial aperture therethrough, and a breach advanceable and retractable in said guide sleeve, means for advancing said broach into cutting contact with the peripheral wall of the aperture in said work piece, the alignment of said broach and said work piece being such that the internal profile produced by broach operation acecgoca' is accurately aligned with: respect to the; out walls of said work. pieces 2. Apparatus of the characterdescribed, for producing a series of work pieces having re-= spective apertures therein which are accurately dimensionally aligned with the; respective outer Walls of the work pieces so that. a pair of adieu-- cent work pieces may be fiiredin mutually end--- abutting' registrab'le relationship on: a common supporting core, said apparatus:- comprising' an elongated work piece holder having a bottom wall. and a pair of spaced opposed side walls extending. therefrom to define: a work receiving channelii open at its end, stop" means fixedswithc respect-to said work holding means for establishing' a. fixed termination point for forward end-- wise movement: of saidwork piece in said channel, clamp" means for retaining said work piece irr-saidcliannel at said terminationpoint, broachguid-ing: means in longitudinal alignment with said channel and with an aperture in said work piece, a. breach carried in said broach-guiding means; means for eriecting relativeapproach movement between said breach and the work clamped as aforesaid to eliect cutting contact between the broach and the wall. of. the: aperture. saidwork piece, the end'of said broach guiding means adjacent said. work having a beli-mouthed flare to receive and abut the forward end of said work piecer and retain it in position during the breaching operation;

BL'Apparatus of the: character described for producing: a series of workpieces having respective apertures therein which are accurately dimensionally aligned with the respective outer walls'of the work pieces so that a pair oil adia-- cent work pieces may be fixed in mutually endabutting registrable relationship on a common supporting. core, said apparatus comprising an elongated: work piece holder having a bottom wall and a pair of spaced opposed side" wallsextending therefrom to define" a work receiving channel open at its ends, stop means fixed-withrespectzto said'work holding means: for establishing a. fixed termination point for forwardiendwise movement ofv said work piece in said channel, clamp means for retaining said work piece in said channel at said termination point, broachguiding means in. longitudinal alignment with said channel and with an aperture in said work piece, saidv broach guiding means comprising a tunneled housing, a guide sleeve telescopingly advanceable: and retractable in said housing said guide sleeve having an axial aperture therethrough, and a broach advanceable and retractable in said guide sleeve, means for effecting endwise movement of said guide sleeve in said housing, further means for effecting endwise movement of said broach in said guide sleeve, the end of said guide sleeve nearest said Work holding, means having a bell-mouthed flare to receive and abut the forwardtend of said work piece and retain it in position during. theibroaching operation,

4. Apparatus of the character described for producing a series of work pieces each having. an aperture therein which is accurately alignedwith respect to its outer surface so that a pair of work pieces thus treated may be fixed in mutually end-abutting registrable relationship on acommon, supporting core, saidapparatus: com-prising abase, a nrelongated' work pieceho'lder fixed; on said base, said holder having a pair of spaced upwardly extending sidewalls to define a work. receiving channel open at its ends, stop means carried-by one of said walls forestablish ing a fixed termination point for.- endwiseiforwardmovement of said work piece in said channel, a clampsupport fixed-with: respect to said base, a. clamping cam. movably carried on said clamp support and movable into contactwith the upper surface of .a work piece in said channel,v a breach, breach-guiding means comprising a tunneled housing fixed with respect to said base; and:- spaced vfrom said work pieceholder, aguide sleeve telescopingly advanceable and retractable'in said housing, said guide sleeve having an aperture therethrough in axial. alignment witlrsaid work receiving channel,v a broach: advanceable and retractable said sleeve: aperture, a lever pivotally fixed on said base, and operatively engaging said guide. sleeve for producing limited endwise reciprocation of said sleeve, a second lever pivotally fixed one-said base and operatively en?- gaging. said broach for producing. limited endwise reciprocation of said breach in said sleeve, cooperative action of both. said levers effecting cutting contact between-the leading end of said breach and the wall of saidapertu-re in said work piece whereby the internal profile. produced by broach operation is accurately aligned with respect to the outer walls: of said work piece.

5. Apparatus of the character described for producing a series of work pieces each having an aperture. therein. which is accurately aligned with respective tozits outer surface so that a pair of work pieces thus treated" may be fixed: in mutually end-abutting registr'able relationship on a common supporting core, said apparatus comprising. an elongated work piece holder having abottom. Wall: and: a pair of spaced, opposed side Walls extending fromv said bottom: wall to'define a Work receiving channel open atits ends-,clamping means' movable with respect to saidsi-de Walls to secure: a work piece in s'aidchannel, breach guiding: means in longitudinal. alignment with said. channel. and with an aperture insaid workpiece, a broach in said guiding means, means for producing relative approach movement between said'bro'ach and saidwork piece whereby to efie'ct breaching contact between said broach andthe walls of said aperture insaid' work piece and said. broachhaving a peripherally serrated cut ting face whereby to produce a serrated inner wall contour in said aperturein fixed relationship to said outer surface, and adapted to receive a serrated core.

FRANK ALBEST;

REFERENGES CITED The following references are of record in the file of this patent: i

UNITED STATES PATENTS Number Name Date- 451,885 Wheeler May; 5,1891 1,421,014. La' Pointe r J une'27, 1922 1,428,968 Schelhammer ;i July, 25-; 1-922 1,905,507 Russell i Apr. 25,1933 1,905,509: Russell e Apr. 25,- 1933 

